Project Summary Alzheimer?s disease (AD) is expected to rise in prevalence from 5 to 16 million Americans by 2050, leading to 43% of deaths among adults over 65. This epidemic is projected to overwhelm healthcare and economic resources, with costs reaching $259 billion in the US in 2017 and $1 trillion by 2050. There is no cure for AD, and no new drugs have been successful in treating the advanced stages of AD-related dementia. A growing body of research suggests that early phases of the disease, such as Mild Cognitive Impairment (MCI) and mild AD, are more likely to be responsive to disease-modifying compounds. Drug development strategies are focused primarily on prevention and early intervention in these high-risk, early AD populations. Advances in clinical trials will require psychometrically rigorous measures capable of detecting subtle cognitive and functional changes indicative of the early disease process. Accurate assessment of functional capacity is especially critical for determining whether investigational treatments provide meaningful therapeutic benefit to everyday functioning. Many tests of functional ability are designed to assess basic activities of daily living (ADLs) such as bathing and eating. However, these skills are typically preserved in MCI and mild AD. In these early phases, subtle but observable deficits are more likely to occur in instrumental ADLs (IADLs) such as shopping and cooking. At present, there are limited options for reliable, sensitive determination of IADL functioning in these critical populations. The shortcomings of traditional functional assessments used in AD drug trials have been well established and include biases in caregiver reports, lack of established reliability, and outdated role-play tasks. Despite growing scientific consensus regarding the need for improved measurement of functional capacity, no new assessments have been developed for use in MCI or mild AD. NeuroCog Trials developed the Virtual Reality Functional Capacity Assessment Tool (VRFCAT) as a computerized performance-based assessment of functional capacity designed to simulate real-world IADLs. Using a realistic virtual environment, the VRFCAT assesses functional performance in the context of a typical trip to the grocery store. Initially developed for use in patients with severe mental illness, the VRFCAT has demonstrated strong psychometric properties and has been implemented in large-scale clinical trials for schizophrenia and major depression. The proposed Fast-Track project will create and validate a new version of the VRFCAT specifically for MCI and mild AD (VRFCAT-MCI) based on established standards for adapting computerized cognitive tests for new target groups. Pilot testing will assess the suitability of the existing VRFCAT and identify any needed software customizations. In Phase II, we will execute a comprehensive validation study to examine the psychometric properties of the VRFCAT-MCI, broadening the commercial and scientific value of this innovative tool in an effort to accelerate breakthrough treatments to delay, slow, and prevent AD.